The aim of this project was to calculate the 2-100p corrections to the radiative decay, b → sγ in electroweak theory. The GRACE, the automatic calculation system of the Feynman amplitude, was developed to treat 2-loop amplitude and the Kobayashi-Maskawa matrix. Then, GRACE counts 4010 diagrams of irreducible 2-loop 3-point functions including the counter terms. We adopted Kinoshita-Civitanovic representation of the Feynman amplitude into the system. All 4010 diagrams were classified into 8 types. In each type, the formulation was established. The structure of the ultra-violet divergence was analyzed and discussed. Some types are numerically investigated.